The present technology relates generally to gas turbine engines and, more specifically, to a system and method for extracting foreign matter through variable bleed valves in gas turbine engines.
Gas turbine engines typically include a compression system, which may consist of a single compressor or multiple compressors rotating at different speeds, for compressing a working fluid, such as air. The compressed air is channeled into a combustor wherein it is mixed with fuel and ignited to generate combustion gases which are channeled to a turbine. The turbine extracts energy from the combustion gasses to power the compressor, as well as to produce useful work to propel an aircraft in flight, or power a load, such as an electrical generator or a ship propeller. The compression system includes variable bleed valves (VBVs) disposed in a fan hub frame having doors that open to provide a bleed path to bleed off compressed air between a booster (low pressure compressor) and a core engine compressor for extracting foreign matter such as sand, ice and the like. Many known compressors include an outlet guide vane (OGV) assembly. Outlet guide vanes have airfoil-like cross sections across which fluids from core engine flow path flows prior to entering the variable bleed valves (VBVs), where a portion of fluids from the core engine flow path bleeds off into a bypass flow path for extraction of foreign particles. The problem associated with conventional bleed valve ducts and valve doors is that larger particles and amounts of particles such as sand, ice and the like are often not sufficiently drawn into the bleed duct. This may further cause erosion and generate stresses in compressor vanes and blades.
There is therefore a desire for a system and method for an enhanced technique for extracting foreign matter in the core engine flow path through variable bleed valves in gas turbine engines.